The present invention relates to (a) methods for retarding the rate at which polymers crosslink to form gels in a subterranean formation, (b) the resulting gels, (c) subterranean formations containing the gels, and (d) compositions for forming the gels.
More and more wells are being drilled into subterranean formations which are at temperatures greater than about 79.4.degree. C. (175.degree. F.). This trend is due to (a) the increasing depth to which wells are drilled to penetrate oil- and gas-bearing subterranean formations and (b) the drilling of wells in regions having shallow, high temperature oil- and/or gas-bearing or geothermal subterranean formations, e.g., the North Sea and the Pacific Rim.
In general, the higher the subterranean temperature, the faster a gelable composition forms a gel in the subterranean formation. In some instances, the gelable composition forms a gel in a time period insufficient for the entire treatment volume of the composition to be injected into the formation.
Accordingly, there is a need for a method for retarding the gelation of a crosslinkable composition in high temperature formations, e.g., in subterranean formations at temperatures above about 79.4.degree. C. (175.degree. F).